In his first professional season in 2006 he split time between Arizona League Mariners appearing in seven games and Single-A Inland Empire 66ers appearing in one game of the California League.
He posted an 0-2 record overall with a 2.25 ERA in 16 innings striking out 17 batters and starting five games.
He picked up the win in relief versus the University of California Los Angeles on April 25 going one inning, surrendering one hit, and striking out two.
Morrow had three strikeouts in two innings against Brigham Young University on January 30.
Morrow went 3-4, with a 4.12 ERA in 60 appearances striking out 66 batters and walking 50.